Sadly you'll probably have a hard time finding any of these parts in shops, they tend to be things one can only get through ordering in or online, and they tend to be expensive.
Well you might be able to get them in 1/8" sizes if you find a paintball shop, but they'll probably be pricey.
Depending on how long you're there, I'd suggest looking on ebay.co.uk and getting items shipped to France.
Ebay.fr isn't fantastic, it doesn't get used anywhere near as much, cultural differences I reckon
You could check leboncoin.fr just in case you are lucky, but it seems unlikely.
As Mimikool suggested technobots.co.uk is reasonably cheap comapred to most other options (including the local ones).
A 3 way valve, is generally called "distributeur pneumatique 3/2", or replace by "electro-pneumatique" for a solenoid DCV.
You will find gardening solenoid valves in hardware stores, but they are just the same as ones found elsewhere...
Oh where you staying ?
Edit: Haha, no JSR was joking
ok which one is correct
